Foley Bulb Traction for Cervical Ripening

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This study aims to determine what type of traction, weighted bag or inner thigh taping, on foley catheters for cervical ripening results in a greater cervical dilation and shorter length of labor.

The primary outcomes are post-ripening dilation of 3 cm or more and time to delivery.

The secondary outcomes are patient pain/comfort rating and method of delivery. The investigators hypothesize that the use a weighted bag will result in a 20% increase in post-ripening dilation of at least 3 cm and a shorter average length of labor.

Condition or disease

Intervention/treatment

Cervical RipeningInduction of Labor

Other: weighted bagOther: leg taping

Detailed Description:

Over the last 20 years the number of induced labors doubled so that over one in five births in 2003 was induced. In response to the rising need for cervical ripening the American College Obstetricians and Gynecologists have stated that both mechanical and prostaglandin ripening is acceptable and safe.

Prior to beginning an induction, the Bishop score (cervical dilation, effacement, station, consistency, and position) is assessed. With Bishop scores less than five, a cervical ripening agent is commonly used. The mechanical dilation with a foley catheter works by both a direct stretching of the lower uterine segment and cervix and a local inflammatory response that releases matrix metalloproteinases and prostaglandins. It is often chosen due to its lower cost, low incidence of systemic side effects, and low risk of hyperstimulation.

Compared to misoprostol a foley with oxytocin was more effective at induction in primiparous patients, more effective at improving the dilation, safe to use after misoprostol, and not associated with an increased risk of uterine rupture in a vaginal birth after cesarean (VBAC). The foley was also shown to have a shorter induction time and less contractile abnormalities than prostaglandin E2 gel and no increased rate of uterine rupture in VBAC attempts. The use of extra-amniotic saline infusion with a foley catheter has been used to augment the mechanical stretching, however this did not decrease the induction time or improve the outcomes. Finally, a Cochrane Database review found that mechanical methods of cervical ripening were equally effective as prostaglandin agents.

Although the safety, efficacy, and side effects of foley catheter ripening have been compared with multiple other methods for cervical ripening, very few studies have compared different protocols for foley placement. One study showed that the use of oxytocin while the foley catheter was in place did not significantly shorten the time to delivery. Levy et al showed that a larger, 80 ml, balloon resulted in a greater post-ripening dilation and a higher number of deliveries in 24hours. No study to date has examined how the traction placed on the foley catheter affects the outcome.

Therefore, we propose doing a randomized controlled study in which the control is the current standard of care at MetroHealth Medical Center of placing a 500cc weight on the foley and placing it to gravity over the end of the bed. The comparison will be the method used at many institutions where the foley catheter is placed on gentle traction and taped to the inner thigh of the patient.

The primary outcomes measured will be a post-ripening dilation of 3cm or more and time to delivery. The secondary outcomes are patient pain/comfort rating and method of delivery.

For the weighted bag, a 500cc saline bag will be taped to an empty Foley bag which will be attached to the cervical Foley catheter. This bag will then be placed to gravity over the end of the bed. The bed will be raised so that the bag does not touch the floor. The foley and the bag will be re-assessed every 30min by the nursing staff.

Other: weighted bag

For the weighted bag, a 500cc saline bag will be taped to an empty Foley bag which will be attached to the cervical Foley catheter. This bag will then be placed to gravity over the end of the bed. The bed will be raised so that the bag does not touch the floor. The foley and the bag will be re-assessed every 30min by the nursing staff.

Active Comparator: leg taping

For the leg taping, the cervical foley catheter will be pulled to gentle traction and attached to the patient's inner thigh using a reclosable foley catheter fastener. The foley catheter and the traction will be assessed every 30min by the nursing staff. The tension will be renewed and the Foley re-adjusted if necessary at each check.

Other: leg taping

For the leg taping, the cervical foley catheter will be pulled to gentle traction and attached to the patient's inner thigh using a reclosable foley catheter fastener. The foley catheter and the traction will be assessed every 30min by the nursing staff. The tension will be renewed and the Foley re-adjusted if necessary at each check.

Time to Delivery [ Time Frame: an average of 20 hours, up to 40 hours ]

Secondary Outcome Measures
:

Patient Pain/Comfort Rating [ Time Frame: an average of 20 hours, up to 40 hours ]

Using a visual analog pain scale, with 0 being no pain and 10 being the most severe pain possible, the patients were asked to assess their pain every hour. The highest pain score recorded while the Foley catheter was in place was used. The data are reported as the median and range.

Time to Foley Expulsion [ Time Frame: an average of 2 hours, up to 12 hours ]

time from Foley placement until it is spontaneously expulsed from the cervix

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